Netinstall requires modem setup help files

When using the netinstall ISO [image on memory stick] to install 20.02 the installer looks for my modem and reports it needs 'configuration' (presumably pc ip address and gateway ip address). This is NOT a wifi issue.
Thus I need to drop to the installer shell.

1. Having tried to edit the installers /etc.rc.local with ip address info might I suggest the installer has a subroutine to allow users to set up their pc ip address and gateway address manually - a linux equivalent to 'bsdconfig networking'.
2. The installer shell has vi editor, which as a first time user struck me as over complex compared with ee editor. If we novices need to drop to the shell to set specific gateway address etc, more support is needed for us in your netinstaller.
3. Of course, a choice of offline installer would work as an alternative.
4. I note that LinuxVoid use an installer with the ability to configure network settings from their page https://docs.voidlinux.org/installation/live-images/guide.html
5. Be aware that without wifi on the system the wifi setup choice in the installer doesn't function - were it to then perhaps the settings for IP address and gateway could use this dialogue.
   Thanks,
   Steve